Hannover 2016 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 58: Poster: Quantum Optics and Photonics IV

Q 58.44: Poster

Thursday, March 3, 2016, 16:30–19:00, Empore Lichthof

Determination of the relative emitter phases in an external-cavity diode laser array — •Mario Niebuhr and Axel Heuer — Institut für Physik und Astronomie, Universität Potsdam, 14476 Potsdam-Golm

Laser diodes (LD) with simultaneous high output power and good beam quality (BQ) are still a matter of ongoing research. One Ansatz which could enable LDs in corresponding applications is the coherent combination of multiple low power, good BQ emitters [1]. The emitters unfortunately tend to de-phase at high pump/output powers and the array loses coherence even when exposed to external seed or feedback.

We intend to investigate the cause of de-phasing by adapting a spatial light modulator based measurement method [2] to determine the relative phase difference between all emitters in an LD array. Measurements were done with an exemplary 9 emitter array radiating at 980nm and forced into coupled operation using an external cavity. Our method allowed for an accurate determination of the preset supermode phase relations as well as a convincing reconstruction of the emitted far field power distribution. Ideas will be presented on how to obtain an understanding of the possible de-phasing mechanisms.

[1] Fan et al, IEEE J. Sel. Top. Quantum Electron., 11, 567 (2005)

[2] Partanen et al., Fringe 2013. Springer Berlin Heidelberg, 879 (2014)